ATSN 2009
Towards an Extensible Agent-based Middleware forSensor Networks and RFID Systems
Dirk BadeUniversity of Hamburg, Germany
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Overview
• Preface
• Introduction
• Challenges
• Proposed Solution▪ Application Scenario
▪ Middleware Architecture
▪ Implementation
• Discussion
• Conclusion and Future Work
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data distributionnetwork
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data distributionnetwork
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Preface
Different Shades of Middleware▪ Sensor Network Middleware
• supports development, maintenance, deployment, execution of sensing-based applications
• focuses on e.g. power & topology management, data transmission & aggregation inside the network
▪ Middleware beyond Sensor Networks• high-level processing & distribution of sensor data
considered asblack box
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Motivation
Sensor Networks & RFID Systems…▪ Although hyped, still in an early state of adoption
▪ High investments, few standards, missing killer applications
▪ Several projects already realized• Designed for a special purpose
• Not interoperable
… will once become widespread▪ More experience with technologies
▪ New emerging requirements
Standards and best-practices will evolve Frequent redesigns of applications & frameworks
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Robustness
Adaptivity
Flexibility
Openness
Heterogeneity
Scalability
Challenges
The Software-Engineering Perspective▪ Evolution of standards and best-practices requires
well designed software infrastructures
▪ Avoiding a Software-Engineering Nightmare
General, non-functional design-goals for a Sensor Network Middleware
• Tolerance towards failures, overloading
• Adaptation of processing to changing conditions
• Deployment in different scales
• Middleware shall be extensible and in parts exchangeable
• Support for different device- and data types
• Deal with drastically increasing loads
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Proposed Solution
Agent-based Event Stream Processing Middleware▪ Agents as …
• design-paradigm for complex distributed processing
• building blocks for different functional roles
▪ Agents are able to …• cope with environmental dynamics
• coordinate among themselves by (a)synchronous message exchangefollowing standardized communication patterns
• exhibit different behaviors according to their context
▪ Event Stream Processing allows to …• efficiently process multiple streams of event data (e.g. from WSN)
• identify meaningful events and complex patterns
• correlate & abstract events to create Application Level Events
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High Level View
ApplicationApplicationApplication
Event ProcessingMiddleware
register
ALE
· Filter· Group· Store· Enrich
· Transform· Aggregate · Create ALE· ...
Tasks
WSN
Base station
RFID
Reader
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Smart Container Monitoring▪ Trading company expects to receive a pallet with TV devices
• Pallet is packed in a Smart Container equipped with several sensors
• Once the container is unpacked, sensor logs are read
• If sensor values exceed a threshold, a mechanic is called to check
▪ States of interest are …• Pallet does not arrive in time
• Pallet arrived, but sensor values indicate possible damage
• Pallet arrived, everything is OK.
▪ Trading Company registers states of interests and information is pushed to the TC once a state is achieved no pulling required
Application Scenario
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Architecture
Net
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dge
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k La
yer
App
licat
ion
Laye
r
Connector
InfrastructureManagement
Low-Level Event Filter
High-Level Event Filter
ApplicationApplicationApplication
group, aggregatetranslate, etc.
get description,ontology, position, etc.
· Create Complex Event Pattern· Create Processing Workflow· Generate Simulation Data
ALEregister
RFIDWSNBase station
Reader
Coordinator
Monitoring/Reporting
EventGenerator
SELECT * FROM MyEventWHERE id BETWEEN x AND y AND (overallacc > 5 OR humidity > 80 OR temperature > 50)+
aggregatemax(temperature)
getInfofrom(warehouseIS, field:containerLog, of:RFID)
getInfofrom(EPCIS@xyz, field:owner,of:RFID)
storeinto(damageDB)
transformto(myProprietaryFormat)use([email protected])
+
groupwin:time(5s)by(id)
Processing WorkflowComplex Event Pattern
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Jadex Event Stream Processing Architecture (JESPA)▪ Core infrastructure has already been implemented
▪ Network Edge • currently supports SunSPOTs, NFC Mobiles, and MagicMap
▪ Network Layer• Lightweight (and BDI-)Agents running on Jadex v2
• HLEF powered by Esper CEP Runtime
▪ Application Layer• Simple Event Generators
• MagicTracker, an Integration of JESPA with MagicMap
Implementation
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Towards meeting the non-functional design-goals▪ Abilities of agents allow different ways to achieve their goals.
▪ Agents are loosely coupled.
▪ Dynamic binding achieved by federated yellow pages.
▪ Functional changes may be handled by injecting or replacing agent types.
▪ Most middleware components are optional
▪ Lightweight agents used for simple tasks, BDI-agents for more sophisticated ones.
▪ Different event sources, data formats and processing devices supported
▪ Processing of events may be easily distributed and parallelized
▪ Security not considered yet
Discussion
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Conclusion & Future Work
Conclusion▪ WSNs more widely deployed, post-WSN data processing more important
▪ Challenging design of event-processing middlewares as standards, requirements and best-practices will change.
▪ Agent-based ESP shall meet these challenges.
▪ JESPA-Prototype incorporates agent-based ESP
Future Work▪ Push the implementation
▪ Develop Monitoring Tools and Event Generators
▪ Foster application integration
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Thank You
Questions ?
Dirk Bade